The present teachings are predicated upon providing a friction material for use in a brake system (e.g., a disc brake system, a drum brake system, or a combination of both) for use with vehicles. For example, the brake system may be used with almost any vehicle (e.g. car, truck, bus, train, airplane, or the like). Alternatively, the brake system may be integrated into assemblies used for manufacturing or other equipment that require a brake such as a lathe, winder for paper products or cloth, amusement park rides, wind turbines, or the like. However, the present teachings are most suitable for use with a passenger vehicle (e.g., a car, truck, sports utility vehicle, or the like).
Generally, a braking system includes a rotor, a caliper body, a support bracket, an inboard brake pad, and an outboard brake pad that are on opposing sides of the rotor. Typically, the inboard brake pad, the outboard brake pad, and the rotor each include planar friction surfaces so that when the brake pads are in contact with the rotor a friction force is generated. The caliper body further includes one or more fingers, one or more piston bores, and a bridge that connects the one or more fingers to the piston bore or two opposing piston bores together. The piston bore houses a piston. The piston bore has a bore axis that the piston moves along during a brake apply and a brake retract. The piston bore may include a fluid inlet, a closed wall, a front opening, and a cylindrical side wall that includes a seal groove located near the front opening. Typically, the fluid inlet is located in the closed wall of the piston bore so that when pressure is applied the fluid will flow into the piston bore. During a pressure apply the fluid will push the piston towards the front opening and into contact with a brake pad that generally includes a pressure plate and friction material with a planar surface and the friction material will contact a planar surface of the rotor on one side and an opposing brake pad will contact the planar surface of the rotor on an opposing side creating friction to stop rotation of the rotor and any component connected to the brake system.
Another type of braking system includes two brake shoes in the hat of the rotor and/or drum so that when a braking force and/or parking brake force is desired the brake shoes are moved into contact with an inner surface of the hat of the rotor (e.g., a drum-in-hat brake system) and/or drum (drum brake system). Typically, brake shoes pivot on one end and have a link on an opposing end that separates the brake shoes so that the brake shoes are moved into contact with an opposing surface to generate a friction force. The link is connected to a pressure plate on each of the brake shoes so that friction material exposed on the pressure plates directly contacts a surface of the drum and/or hat to generate a friction force.
During these friction events the friction members (e.g., brake pad or brake shoe) contacts a moving part (e.g., rotor or drum respectively) and the friction material gradually slows the moving part until a complete stop is achieved. During the contact between the friction material and the moving part wear occurs so that a portion of the friction material, moving part, or both gradually becomes worn over time. The speed at which the friction material and moving part wear may be increased or decreased based upon the composition of each. The composition of the friction material may be adjusted to increase one property which may result in a decrease in another property. These properties may be balanced in order to provide a friction material that achieves predetermined braking characteristics.
Examples of some friction materials are disclosed in U.S. Pat. Nos. 7,297,728; 8,172,051; and U.S. Patent Application Publication Nos. 2002/0169231; 2004/0146702; 2006/0151268; 2007/0219289; and 2008/156226 and U.S. International Application Nos. WO99/53215; WO2011/049576; and WO2013/048627 all of which are expressly incorporated herein by reference for all purposes. What is needed is a friction material that provides a high level of braking without deteriorating and/or deteriorating the moving part. What is needed is an improved friction material that generates a high level of friction without creating a large amount of brake dust or brake powder. It would be attractive to have a friction material that is bonded together by a material that both keeps all of the materials together but also assists in creating friction.